tree-into-ssa.c (rewrite_stmt): Remove clobbers for variables we rewrite into SSA form.

2012-08-07  Richard Guenther  <rguenther@suse.de>

	* tree-into-ssa.c (rewrite_stmt): Remove clobbers for variables
	we rewrite into SSA form.
	(rewrite_enter_block): Adjust.
	* gimple-iterator.c (gsi_replace): Also allow replacement with
	a stmt without a lhs.
	* tree-ssa-live.c (remove_unused_locals): Remove code handling
	clobbers of SSA names.
	* tree-nested.c (convert_local_reference_stmt): Remove clobbers
	for variables we access through the local chain.
	* tree-cfg.c (verify_gimple_assign_single): Verify clobbers
	clobber full decls only.

From-SVN: r190200

gcc/ChangeLog

@@ -1,3 +1,17 @@
+2012-08-07  Richard Guenther  <rguenther@suse.de>
+
+	* tree-into-ssa.c (rewrite_stmt): Remove clobbers for variables
+	we rewrite into SSA form.
+	(rewrite_enter_block): Adjust.
+	* gimple-iterator.c (gsi_replace): Also allow replacement with
+	a stmt without a lhs.
+	* tree-ssa-live.c (remove_unused_locals): Remove code handling
+	clobbers of SSA names.
+	* tree-nested.c (convert_local_reference_stmt): Remove clobbers
+	for variables we access through the local chain.
+	* tree-cfg.c (verify_gimple_assign_single): Verify clobbers
+	clobber full decls only.
+
 2012-08-07  Richard Guenther  <rguenther@suse.de>
 
 	* gimple.h (gimple_phi_set_result): Adjust SSA_NAME_DEF_STMT.

gcc/gimple-iterator.c

@@ -427,7 +427,7 @@ gsi_replace (gimple_stmt_iterator *gsi, gimple stmt, bool update_eh_info)
   if (stmt == orig_stmt)
     return;
 
-  gcc_assert (!gimple_has_lhs (orig_stmt)
+  gcc_assert (!gimple_has_lhs (orig_stmt) || !gimple_has_lhs (stmt)
 	      || gimple_get_lhs (orig_stmt) == gimple_get_lhs (stmt));
 
   gimple_set_location (stmt, gimple_location (orig_stmt));

gcc/tree-cfg.c

@@ -3930,6 +3930,14 @@ verify_gimple_assign_single (gimple stmt)
       return true;
     }
 
+  if (gimple_clobber_p (stmt)
+      && !DECL_P (lhs))
+    {
+      error ("non-decl LHS in clobber statement");
+      debug_generic_expr (lhs);
+      return true;
+    }
+
   if (handled_component_p (lhs))
     res |= verify_types_in_gimple_reference (lhs, true);
 

gcc/tree-into-ssa.c

@@ -1323,12 +1323,12 @@ rewrite_debug_stmt_uses (gimple stmt)
    definition of a variable when a new real or virtual definition is found.  */
 
 static void
-rewrite_stmt (gimple_stmt_iterator si)
+rewrite_stmt (gimple_stmt_iterator *si)
 {
   use_operand_p use_p;
   def_operand_p def_p;
   ssa_op_iter iter;
-  gimple stmt = gsi_stmt (si);
+  gimple stmt = gsi_stmt (*si);
 
   /* If mark_def_sites decided that we don't need to rewrite this
      statement, ignore it.  */
@@ -1362,9 +1362,24 @@ rewrite_stmt (gimple_stmt_iterator si)
     FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS)
       {
 	tree var = DEF_FROM_PTR (def_p);
-	tree name = make_ssa_name (var, stmt);
+	tree name;
 	tree tracked_var;
+
 	gcc_assert (DECL_P (var));
+
+	if (gimple_clobber_p (stmt)
+	    && is_gimple_reg (var))
+	  {
+	    /* If we rewrite a DECL into SSA form then drop its
+	       clobber stmts and replace uses with a new default def.  */
+	    gcc_assert (TREE_CODE (var) == VAR_DECL
+			&& !gimple_vdef (stmt));
+	    gsi_replace (si, gimple_build_nop (), true);
+	    register_new_def (get_or_create_ssa_default_def (cfun, var), var);
+	    break;
+	  }
+
+	name = make_ssa_name (var, stmt);
 	SET_DEF (def_p, name);
 	register_new_def (DEF_FROM_PTR (def_p), var);
 
@@ -1372,7 +1387,7 @@ rewrite_stmt (gimple_stmt_iterator si)
 	if (tracked_var)
 	  {
 	    gimple note = gimple_build_debug_bind (tracked_var, name, stmt);
-	    gsi_insert_after (&si, note, GSI_SAME_STMT);
+	    gsi_insert_after (si, note, GSI_SAME_STMT);
 	  }
       }
 }
@@ -1439,7 +1454,7 @@ rewrite_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
      of a variable when a new real or virtual definition is found.  */
   if (TEST_BIT (interesting_blocks, bb->index))
     for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
-      rewrite_stmt (gsi);
+      rewrite_stmt (&gsi);
 
   /* Step 3.  Visit all the successor blocks of BB looking for PHI nodes.
      For every PHI node found, add a new argument containing the current

gcc/tree-nested.c

@@ -1727,6 +1727,20 @@ convert_local_reference_stmt (gimple_stmt_iterator *gsi, bool *handled_ops_p,
       *handled_ops_p = false;
       return NULL_TREE;
 
+    case GIMPLE_ASSIGN:
+      if (gimple_clobber_p (stmt))
+	{
+	  tree lhs = gimple_assign_lhs (stmt);
+	  if (!use_pointer_in_frame (lhs)
+	      && lookup_field_for_decl (info, lhs, NO_INSERT))
+	    {
+	      gsi_replace (gsi, gimple_build_nop (), true);
+	      break;
+	    }
+	}
+      *handled_ops_p = false;
+      return NULL_TREE;
+
     default:
       /* For every other statement that we are not interested in
 	 handling here, let the walker traverse the operands.  */

gcc/tree-ssa-live.c

@@ -773,9 +773,6 @@ remove_unused_locals (void)
 	    if (gimple_clobber_p (stmt))
 	      {
 		tree lhs = gimple_assign_lhs (stmt);
-		lhs = get_base_address (lhs);
-		if (TREE_CODE (lhs) == SSA_NAME)
-		  lhs = SSA_NAME_VAR (lhs);
 		if (TREE_CODE (lhs) == VAR_DECL && !is_used_p (lhs))
 		  {
 		    unlink_stmt_vdef (stmt);